Godzilla has doubled in size since it appeared in 1954. Why?

One proposal is that it reflects increasing anxiety: Nathaniel J. Dominy, Ryan Calsbeek, Godzilla’s extraordinary growth over time mirrors an increase in Anthropocene angst, Science, 28 May, 2019:

[Susan] Sontag argued that our taste for disaster films is constant and unchanging. On the contrary, we suggest that Godzilla is evolving in response to a spike in humanity’s collective anxiety. Whether reacting to geopolitical instability, a perceived threat from terrorists, or simply fear of “the other,” many democracies are electing nationalist leaders, strengthening borders, and bolstering their military presence around the world.

Oleg Sobchuk is not buying it, The “Science” of Godzilla in Science, Medium, 26 June 2019:

Personally, I think that another — simpler and less dramatic — hypothesis is more likely. More likely because it concerns not a particular film but a general pattern of the cultural evolution of art.

This hypothesis has to do with a common, though not very well studied, phenomenon of the intensification of artistic stimuli over time. Mnay artistic “devices” — techniques of manipulating pleasant emotions in the audience — tend to be used in more intense ways during their evolution. Godzilla is a device, similarly to King Kong or any other monster in the kaiju genre featuring giant monsters: somehow, the size on its own may be enough to evoke some pleasant fear in us.

Makes sense to me. Spreading anxiety is a reasonable way to think about the spread of Godzilla films, but stimulus intensification is a better way to talk about the monster's size.